Why won't Final Cut Pro open!?

I'm using a Mac pro. Yesterday I installed the Final Cut Pro 7 and tried it out for the first time, everything was ok, but later on that day, when I tried to open it again, it didn't open, it showed that FCP's starting up and stuff, then it made me enter my password, after that, the choose setup dialog appeared, but it was not clickable! I was unable to close the FCP so I had to go the activity monitor to force it quit. I tried to open the app again, the same thing happened except the choose setup dialog didn't appear. Once awhile that dialog would appear other time it did not. I don't know what's going on! Any one has any idea please help me! I've cleared the preference and stuff but nothing did seem to work! Please help!